Synthesis of Maternal Transfer of Mercury in Birds: Implications for Altered Toxicity Risk

Ackerman, J. T. and Herzog, M. P. and Evers, D. C. and Cristol, D. A. and Kenow, K. P. and Heinz, G. H. and Lavoie, R. A. and Brasso, R. L. and Mallory, M. L. and Provencher, J. F. and Braune, B. M. and Matz, A. and Schmutz, J. A. and Eagles-Smith, C. A. and Savoy, L. J. and Meyer, M. W. and Hartman, C. A.

Environ Sci Technol (2020) 54: 2878–2891

DOI: 10.1021/acs.est.9b06119

Abstract

Maternal transfer is a predominant route of methylmercury (MeHg) exposure to offspring. We reviewed and synthesized published and unpublished data on maternal transfer of MeHg in birds. Using paired samples of females’ blood (n = 564) and their eggs (n = 1814) from 26 bird species in 6 taxonomic orders, we conducted a meta-analysis to evaluate whether maternal transfer of MeHg to eggs differed among species and caused differential toxicity risk to embryos. Total mercury (THg) concentrations in eggs increased with maternal blood THg concentrations; however, the proportion of THg transferred from females to their eggs differed among bird taxa and with maternal THg exposure. Specifically, a smaller proportion of maternal THg was transferred to eggs with increasing female THg concentrations. Additionally, the proportion of THg that was transferred to eggs at the same maternal blood THg concentration differed among taxonomic orders, with waterfowl (Anseriformes) transferring up to 382% more THg into their eggs than songbirds (Passeriformes). We provide equations to predict THg concentrations in eggs using female blood THg concentrations, and vice versa, which may help translate toxicity benchmarks across tissues and life stages. Our results indicate that toxicity risk of MeHg can vary among bird taxa due to differences in maternal transfer of MeHg to offspring.

Citation

Ackerman, J. T., Herzog, M. P., Evers, D. C., Cristol, D. A., Kenow, K. P., Heinz, G. H., Lavoie, R. A., Brasso, R. L., Mallory, M. L., Provencher, J. F., Braune, B. M., Matz, A., Schmutz, J. A., Eagles-Smith, C. A., Savoy, L. J., Meyer, M. W., & Hartman, C. A. (2020). Synthesis of Maternal Transfer of Mercury in Birds: Implications for Altered Toxicity Risk. Environ Sci Technol, 54(5), 2878–2891. https://doi.org/10.1021/acs.est.9b06119 Animals, Female, Humans, Birds, Environmental Monitoring, *Water Pollutants, Chemical, Eggs, Maternal Exposure, *Mercury, *Methylmercury Compounds

Keywords

• Animals
• Female
• Humans
• Birds
• Environmental Monitoring
• *Water Pollutants
• Chemical
• Eggs
• Maternal Exposure
• *Mercury
• *Methylmercury Compounds